Metabolism Test

I’ve been thinking about seeing a nutritionist for sometime now and recently went to a seminar with Delina Rahmate (BHSc Nutritional Medicine) and Therese Fossheim, a Physiotherapist & Exercise Scientist. The seminar was a Sport Nutrition Seminar aimed at improving performance & recovery. The focus was on how insufficient fuel for your metabolism is a common contributor to fatigue, injuries and bonking and that eating smart can boost your performance, improve efficiency and assist in recovery.

At the seminar I was introduced to metabolism testing and thought it would benefit me in the lead up to Ironman Cairns, 2018. I had time before the training for Cairns started to change my fat burning by making changes in my diet. I could do the test at PhysioLogic and then Delina would use the results to help me with my nutrition – for improved performance and recovery.

I’m not a scientist and have never been really interested in science so I’ll give you the plain jane version, but if you’re interested there’s lots more info at PhysioLogic and Jupiter Health.

The Test

Basically I had to do two tests, one to determine my resting metabolic rate and an exercise test to measure my exercise metabolic rate. The tests would show me what rate of carbs, fat and protein I should have for my metabolism – not the amount that is a general guide for someone who is my age, weight and height, but really specific for me.

This test is conducted at rest and during exercise to give a complete profile of how your body burns fuel (carbohydrate and fat)

The resting metabolism test was really easy. Testing resting metabolism allows me to know how much fuel I burn. Each person’s resting/basal metabolism is 60-75% of the total calories their body burns daily.

For the resting test, all I had to do was relax, wear a mask and breathe in and out while lying on a bed for around 15 minutes. I smashed that test! I’ve been training my whole life to relax. The test measured the amount of oxygen I was taking in and the amount of carbon dioxide I was producing – breathing out.

The exercise test was a little more difficult. I had to work out – easy at first and then hard until I could go no longer. It was described to me a little like a beep test. The first few levels you know you can do, but you just have to keep pushing yourself further than you think you can go. I even had to practise jumping off the treadmill at the end and not falling off (and ending up in a blooper’s reel!)

I started on the treadmill, walking, then it gradually increased to a run, then Tom (my tester) added in inclines and then kept putting up the incline. It got to the point where I was physically heaving until I could take it no more and jumped off the treadmill.

I didn’t know how I did at the time because I rarely run on a treadmill, so I have nothing to compare the speed and incline with.

I did, however, like the cheering I was getting from Tom. He told me he was going to cheer from the side and he did. He certainly kept me going a little longer than I would’ve if I was just running on my own. Clapping his hands and telling me how great I was doing, and that I can push through and just go a little harder. He was my own personal cheer squad.

The Results

First things first … my VO2max was in the 95th percentile for my age at 50.6ml/kg/min. I don’t get exactly what that means but I do get 95th percentile! Go me!

But, my exercise fat burning ability is in the low range. At rest I burn 51% fat and 49% carbohydrate. The fat percentage should be around 60% – 80%. Interestingly, my resting expenditure is 1271 calories per day and with the amount of exercise I do my calorie expenditure goes up to around 2800 calories a day.

My resting metabolism is suboptimal, the more suboptimal it is the more I am likely to experience problems with fatigue and weight management.

My fuel burning profile below, should be more fish shape and I should be burning more fat at a lower heart rate, although the crossover point is good. It could be pushed a little higher but it’s in a pretty good position at the moment.

What does it mean?

By doing the test I can see where my body is at during rest and exercise and why it may not be performing as well as I’d like it to. It also means that I have a base on which to change. It’s almost futile guessing what I should change and why without knowing some basic details.

By burning more fat for longer I can perform better for longer during an event. If you’ve heard of ‘bonking’ or ‘hitting the wall’ this is what happens, the body is not able to provide the fuel to keep going. The body is able to store a lot more fat than carbohydrates. Once my heart rate gets to 148 bpm I start burning more carbohydrates and as the body stores less carbohydrates it is easier to run out and bonk or hit the wall.

Where to from here?

Now that I know these results I can do two things to improve my fat burning ability.